The invention relates to the field of optical modulators, and in particular to a method of modulating light utilizing shock waves in a crystal structure.
There are very few ways to generate and manipulate coherent radiation. The generation of coherent radiation is imperative for interferometry and other important optical techniques. Existing practical sources of coherent radiation are quantum lasers and free electron lasers. The technology presented in accordance with the invention represents a new source of coherent radiation.
Uses for terahertz radiation range from the new field of THz spectroscopy, to fundamental studies of phonon dynamics, to an alternative to harmful x-rays in medical imaging to security screening devices able to penetrate clothing to detect explosives or other weapons. However, the generation of narrow bandwidth radiation in the terahertz regime has proven to be a difficult task. While substantial progress has been made, existing sources of THz radiation have substantial shortcomings that limit their practical use.
Generally, existing techniques are limited to 1–10 microwatt power outputs, requiring long exposure times for probing. Quantum cascade lasers can be used to generate narrow bandwidth coherent THz radiation, but must be cooled below room temperature and are limited to frequencies above about 2 THz. Photoconductive approaches can generate only broad bandwidth THz radiation up to around 2 THz and require cooling the photoconductive element below room temperature.
Nonlinear frequency downconversion approaches can provide coherent radiation but are also limited in their efficiency, providing power outputs in 1–10 microwatt range.